Shedding light on dark DNA Most textbook definitions of evolution state that it occurs in two stages: mutation followed by natural selection. DNA mutation is a common and continuous process, and occurs completely at random.
The average adult only eats 15 grams of fiber per day. Women need 25 grams of fiber per day, and men need 38 grams per day, according to the Institute of Medicine.
Recommendations. The 2010 Dietary Guidelines for Americans suggest that you eat at least 14 grams of dietary fiber per 1,000 calories. Using the recommended caloric intakes in the Guidelines, sedentary men between the ages of 19 and 30 should eat 33.6 to 36.4 grams of fiber per day. These values increase to 36.4 to 39.2 grams for moderately active and 42 grams or more for active men.